PT  - JOURNAL ARTICLE
AU  - Mark H. Ebell
AU  - Linda L. White
AU  - Tracy Casault
TI  - A Systematic Review of the History and Physical Examination to Diagnose Influenza
AID  - 10.3122/jabfm.17.1.1
DP  - 2004 Jan 01
TA  - The Journal of the American Board of Family Practice
PG  - 1--5
VI  - 17
IP  - 1
4099  - http://www.jabfm.org/content/17/1/1.short
4100  - http://www.jabfm.org/content/17/1/1.full
SO  - J Am Board Fam Med2004 Jan 01; 17
AB  - Background: Although influenza is a commonly encountered condition in primary care, and diagnosis is increasingly important given the availability of new treatments, there has been no systematic review of the evidence on clinical diagnosis.Methods: This was a systematic review of the literature with meta-analysis where appropriate. We included cohort studies and randomized trials that compared the history and physical examination with a reference laboratory test for the diagnosis of influenza A and/or B. The primary outcomes were the sensitivity, specificity, likelihood ratios, and area under the receiver-operating characteristic (ROC) curve.Results: Seven studies reported the sensitivity and specificity for a total of 59 variables. We combined studies of influenza A or B alone with those of influenza A and B. Rigors [likelihood ratio (LR) +7.2], the combination of fever and presenting within 3 days of the onset of illness (LR +4.0), and sweating (LR +3.0) were best at ruling-in influenza when present. When absent, the following decreased the likelihood of influenza: any systemic symptoms (LR −0.36), coughing (LR −0.38), not being able to cope with daily activities (LR −0.39), and being confined to bed (LR −0.50). Cough, nasal congestion, and fever (subjective or objective) had the highest calculable areas under the ROC curve.Conclusions: Individual signs and symptoms are of limited value for the diagnosis of influenza. Development of clinical decision rules that systematically combine symptoms may be a more useful strategy.